The present invention relates to floor machines and more particularly to vertical axis, rotary floor treating machines.
Heretofore, a wide variety of vertical axis floor treating machines have been proposed for brushing, scrubbing and/or polishing a floor surface. Such machines typically include a frame, a pivotable operator's control handle and a generally circular floor treating element driven by an electric motor. The floor treating element is rotated about a central, vertical axis and may take the form of a brush or a polishing pad, for example.
Relatively low speed vertical axis machines typically mount the motor centrally of the floor treating element. The element is then evenly pressed onto the floor surface by the weight of the machine. The machine is moved in a sweeping arc by application of pressure on the control handle. Low speed machines typically operate in the 300 to 400 RPM range. An example of one such floor treating machine may be found in U.S. Pat. No. 3,264,674, entitled FLOOR TREATING MACHINES and issued Aug. 9, 1966, to D. I. Doyle, Jr. et al.
High speed vertical axis floor treating machines operate at speeds in excess of 1000 RPM. Such machines are significantly more effective than more conventional, low speed machines. The weight of the machine, however, cannot be supported entirely on the brush or pad since current draw or power requirements would become excessive. The machines, also, would be extremely difficult to control. As a result, high speed vertical axis machines typically include a pair of ground engaging wheels to help support the machine. Examples of high speed vertical axis machines may be found in U.S. Pat. No. 4,115,890, entitled HIGH-SPEED POLISHING MACHINE and issued on Sept. 26, 1978, to Burgoon and U.S. Pat. No. 4,122,576, entitled HIGH-SPEED FLOOR TREATING MACHINE and issued on Oct. 31, 1978, to Bevington et al.
Problems have been experienced with ease of operation and control of the brush or pad aggressiveness of the high speed machines. Also, problems have been experienced with maintaining proper contact of the high speed pad or brush when different thickness pads are substituted. Such substitution requires adjustment of the wheel height of the machine. Further, prior machines have not permitted effective and efficient edge control. Heretofore, in order to increase the pressure along one side of the pad when "edging" the machine, it was necessary to reef the whole machine over and balance it on one wheel. Such an operating mode can present a danger to the operator due to loss of control of the machine.